CF1430F Realistic Gameplay

樸素做法暴力DP，O(nk)過不去。。。

 1 #include <cmath>
 2 #include <cstdio>
 3 #include <cstring>
 4 #include <algorithm>
 5 #define N1 2005
 6 #define ll long long 
 7 using namespace std;
 8 
 9 int n,p;
10 int l[N1],r[N1],a[N1];
11 ll f[N1][N1];
12 ll linf=0x3f3f3f3f3f3fll;
13 
14 int main()
15 {
16     freopen("a.txt","r",stdin);
17     scanf("%d%d",&n,&p);
18     for(int i=1;i<=n;i++) scanf("%d%d%d",&l[i],&r[i],&a[i]);
19     for(int i=0;i<=n;i++) for(int k=0;k<=p;k++) f[i][k]=linf;
20     f[0][p]=0; l[n+1]=r[n]+1;
21     for(int i=1;i<=n;i++)
22     {
23         for(int k=0;k<p;k++)
24         {
25             if(a[i]%p<=k)
26             {
27                 if(a[i]/p<=r[i]-l[i]) 
28                 {
29                     f[i][k-a[i]%p]=f[i-1][k]+a[i]/p;
30                     if(a[i]/p+1<=l[i+1]-l[i]) f[i][p]=min(f[i][p],f[i-1][k]+a[i]/p+1);
31                 }
32             }
33             if(a[i]%p>k)
34             {
35                 if(a[i]/p+1<=r[i]-l[i]) 
36                 {
37                     f[i][k+p-a[i]%p]=f[i-1][k]+a[i]/p+1;
38                     if(a[i]/p+2<=l[i+1]-l[i]) f[i][p]=min(f[i][p],f[i-1][k]+a[i]/p+2);
39                 }
40             }
41         }
42         if(a[i]%p)
43         {
44             if(a[i]/p<=r[i]-l[i]) 
45             {
46                 f[i][p-a[i]%p]=f[i-1][p]+a[i]/p;
47                 if(a[i]/p+1<=l[i+1]-l[i]) f[i][p]=min(f[i][p],f[i-1][p]+a[i]/p+1);
48             }
49         }else{
50             if(a[i]/p-1<=r[i]-l[i]) 
51             {
52                 f[i][0]=f[i-1][p]+a[i]/p-1;
53                 if(a[i]/p<=l[i+1]-l[i]) f[i][p]=min(f[i][p],f[i-1][p]+a[i]/p);
54             }
55         }
56         
57     }
58     ll ans=linf;
59     for(int k=0;k<=p;k++) ans=min(ans,f[n][k]*p+p-k);
60     if(ans==linf) puts("-1"); else printf("%lld\n",ans);
61     return 0;
62 }